1EBC Newsletter June 2014, Issue 59

03 RESEARCH IN GERMANY 08 OptIMISED

RENOvAtION06 RELIABLE REtROfIttING

Issue 59 | June 2014

EBC NEWS

10 tHERMAL pERfORMANCE IN tHE REAL WORLD 12 A NEW CONCEpt fOR

HvAC SYStEMS

EBC is a programme of the International Energy Agency (IEA)

14 NEW AND COMpLEtED pROJECtS

2 EBC Newsletter June 2014, Issue 59

Cover pictures - EnOB air measuring

station LOBSTER at KIT Karlsruhe

Source: © fbta KIT, Karlsruhe

Foto: Moritz Karl

Published by AECOM Ltd on behalf of

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Communities Programme, functions

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Views, findings and publications of the

EBC Programme do not necessarily

represent the views or policies of the

IEA Secretariat or of all its individual

member countries.

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Our common ground sets a solid foundation for international collaboration

Dear Reader,

Since the lead article in this edition deals with improving the energy

performance of buildings in Germany, it was absolutely clear to me that

as they are a close neighbour and partner of Austria, I should emphasise

the importance of international collaboration. Despite trivial rivalries

between our two countries over activities such as football or skiing, there

is an excellent working relationship between our innovation sectors. And

between Germany, Austria, and Switzerland, there are few linguistic

and cultural barriers or climatic differences in comparison with other

countries. Where they exist, removing barriers to cooperation is essential

to our work. The well established structure provided by EBC supports

wider collaboration, not only between neighbouring countries, but also

across continents and cultures. In recent times, this has been successfully

put into practice with the completion of an EBC project on energy efficient

communities.

Agreeing common terminology is the starting point for new EBC research

to improve occupant behaviour simulation. This continues the topic of

a recently concluded project that has advanced our knowledge on the

analysis and evaluation methods that can be used to calculate total

energy use in buildings. Two of our research studies are now examining

how renovation can be improved: one is looking at optimisation in terms

of cost effective energy use and carbon dioxide emissions reductions,

while the other is creating a new approach to assessing the reliability

of energy efficient retrofitting. Another two projects are investigating

thermal performance, by improving the accuracy of building envelope

measurements and by proposing novel heating, ventilation and air

conditioning systems based on high temperature cooling and low

temperature heating.

This newsletter gives you an insight into some of our exceptional projects.

I hope you enjoy reading about the evolution of our new ideas and the

interesting solutions we are developing.

Isabella Zwerger

EBC Executive Committee Member for Austria

3EBC Newsletter June 2014, Issue 59

The 'Research for Energy Optimized Building (EnOB)'

research programme has been managed by the Ger-

man Federal Ministry for Economic Affairs and En-

ergy since 1995. The objectives of this programme are

to accelerate the implementation of innovative, energy

efficient building technologies into practice and their

scientific evaluation within a real-life context. During

the EnOB initiative, more than 50 individual buildings

have been monitored and evaluated for more than two

years, while about a further 40 buildings are pres-

ently being planned, built or monitored. The majority

of new buildings investigated have been offices or ad-

ministrative buildings and form the largest group in-

vestigated. Educational buildings constitute the sec-

ond largest group of demonstration buildings, serving

as 'living labs' for optimized learning environments

supplied with sustainable energy. The conclusions

drawn from the analysis are presented below.

Demonstrating technologies By delivering valuable results and experiences from

practice, demonstration programmes are essential to

implementing the outcomes from research and devel-

opment (R&D) on building technologies. Systematic

monitoring of high performance buildings allows a

comparison of key performance indicators, as well as

an evaluation of newly implemented technologies in

a real building context. Demonstration buildings also

Building energy efficiency research in Germany

Markus Kratz

The Research for Energy Optimized Building initiative has supported the planning, construction and monitoring of ground-breaking demonstration buildings for almost 20 years. Through this experience, practical urban scale net zero-energy solutions are edging towards reality.

Primärenergie Endenergie

EnOBPrimary Energy

EnOBEnd-use Energy

EnBopEnd-use Energy

BMVBS EnEV 2009

kWh/m²a kWh/m²a kWh/m²a Heat 46 55 74 110 Electricity (total) 82 85 Electricity (HVAC + lig 53 20 0 0 HVAC+L Electricity (user) 90 35 User

189 110 156 195

Anteil Nutzerverbräuche an Gesamt 32% Endenergie48% Primärenergie

46 5574

11053

20

90

35

82

85

0

50

100

150

200

250

EnOBPrimary Energy

EnOBEnd-use Energy

EnBopEnd-use Energy

BMVBS EnEV 2009

kWh/m²a

Heat Electricity (HVAC + lighting) Electricity (user) Electricity (total)

Primary Energy End-Use Energy

Energy consumption in 12 selected EnOB office buildings compared to consumption-based energy certificates (BMvBS EnEv 2009) and to 30 recently built modern office buildings according to an evaluation within the ‘energy-oriented operation optimisation’ research theme (EnBop).

Energy consumption in EnOB office buildings

4 EBC Newsletter June 2014, Issue 59

serve as proofs of concept that stimulate replication

at a broader scale. Further, economic benefits and

occupant acceptance of new building concepts and

technologies can be investigated, enhancing the scope

from evaluation of energy efficiency to a more holistic

view on sustainability.

Reduced energy consumptionThe level of energy consumption of EnOB buildings

is significantly lower than current target values in

German legislation. The average end use energy con-

sumption (including user-related electricity consump-

tion) of the investigated office buildings with a value

of 110 kWh/(m² year) is about 45% below the refer-

ence value in the German Building Energy Saving

Regulation (EnEV 2009). More than 30% of the end

use energy and almost half of the primary energy

consumed in the EnOB office buildings can be attrib-

uted to electricity consumption directly related to the

building usage. The average emissions of greenhouse

gases are about 37 kg/(m² year) CO2-equivalent and

are dominated by the 76% share related to electricity

consumption. Auxiliary energy for building services

systems would also have a strong influence on a build-

ing’s total energy use. Therefore, careful planning,

sizing and controls for all components are important

to achieve high seasonal performance factors of all

installed HVAC systems, for example ventilation with

heat recovery or ground-coupled heat pumps.

Flexibility in energy supply and demand A very low heating energy demand similar to the Pas-

sivhaus standard has proved to be a reliable basis for

proceeding towards 'net zero-energy' or 'net-plus-

energy' buildings. Highly energy efficient buildings

offer maximum flexibility for different energy supply

strategies, which could be either an 'all-electric' ap-

proach (for example PV with heat pumps) or combined

heat and power (CHP) generation. This approach is

particularly interesting for larger or existing build-

ings. Small scale CHP units based on biomass are

still a topic of research. Exploiting low temperature

sources such as waste or groundwater heat reduces

the required energy quality by minimizing the exergy

level. However, as mentioned above, the influence of

energy saving building concepts can be partially can-

celled out by end use specific electricity consumption.

For this reason, not only improved efficiency, but also

carbon-neutral generation of electricity are very im-

portant to achieve climate neutral buildings.

In brief, building load and energy generation profiles

have to be harmonized for an overall optimization of

'green' energy use. With a highly fluctuating supply

side due to an increasing share of renewable energy,

the need for more flexibility on the demand side is

also growing. Therefore, the interactions between

buildings and the grid infrastructure such as electric-

ity, gas and district heating becomes more important.

Buildings are starting to change towards a more ac-

tive role in the energy system in terms of load shift-

ing (for example by energy storage), load management

and on-site energy generation in connection with the

grids. This also allows ‘net zero-energy’ solutions at

larger urban scales (urban quarter, city, region), par-

ticularly for the existing building stock.

Technology matrix

Technology matrix with a sample of the technological approaches applied in individual EnOB demonstration buildings since 1995. The research has been funded under the following themes: "Energy-optimised new buildings" (EnBau), "Energy-oriented refurbishment" (EnSan), "Energy-efficient schools" (Eneff:Schule).

5EBC Newsletter June 2014, Issue 59

Economic evaluationComparisons with the German building cost index

show that innovative energy concepts aligned with

the current EnOB goals can be put into practice with

similar construction costs to conventional buildings.

Initial results on building-specific energy costs indi-

cate they are significantly lower than those widely

used in the real estate sector to estimate the antici-

pated energy costs during early planning phases. But,

to derive reliable life-cycle costs from demonstration

buildings requires much longer monitoring periods

compared to energy monitoring.

Energy efficient technologiesAn essential feature of the EnOB demonstration build-

ings is well-matched integration of energy efficient

technologies with the architecture and the complete

building concept. Thermal insulation, ventilation and

the interaction between use of daylight and solar con-

trol and glare protection have a fundamental effect on

the building form, floor plan and façade design.

Passive cooling can maintain thermal comfort ac-

cording to the adaptive model under central-Euro-

pean summer conditions, if all necessary design fea-

tures are incorporated, particularly avoiding high

solar gains. Discharging heat stored in internal build-

ing mass by the use of natural heat sinks has been

successfully demonstrated. Examples include night

ventilation with ambient air, thermally activated con-

crete slabs or geothermal heat sinks. Geothermal heat

sinks can decouple the indoor from the outdoor cli-

mate to a large extent even during very hot periods.

Proper commissioning of the buildings and energy-

optimized building operation were identified as key

factors to match expected and monitored performance

data. Various tools have already been developed and

tested in EnOB buildings to tap the huge potential en-

ergy savings by improving building operation. These

include automated data processing, visualization and

fault detection, as well as model based optimization.

Advanced and novel materials (capillary-active inte-

rior insulation, vacuum insulation, nanogel-plaster)

allow thinner insulation layers and are the focus of

current research activities. This includes prefabrica-

tion of building elements to improve quality and the

installation time. As an example, large-size, prefabri-

cated wall panels with vacuum insulation have been

applied successfully in demonstration buildings. The

functionality and reliability of vacuum insulation

systems were tested after several years of operation.

Although a significant risk remains in the construc-

tion process, the result was that there were almost no

failures of elements that had been originally installed

without damage – even after 10 years.

Occupant satisfactionThe monitoring of the demonstration buildings was

accompanied by questionnaire-based surveys. One

major finding was that the occupants' need for inter-

acting with the indoor environment significantly in-

fluences their satisfaction with the workplace. Other

parameters dominating the acceptance are privacy

and the noise level in the office, which are affected by

the type of office and space design. In general, stand-

ardized occupant surveys proved to be an effective

measure for building operation assessment. As oc-

cupant behaviour strongly influences the energy con-

sumption of buildings, more research is necessary to

determine typical behavioural patterns for different

building types. From these, improved probabilistic

models can then be developed for more reliable simu-

lation results during planning.

Further informationwww.enob.info

Launched in 2009, BUILD Up is a European Commission initiative aiming to reduce the energy consumption of buildings across Europe.

www.buildup.eu promotes the effective implementation of energy saving measures in buildings and offers free access to a wide range of information on best practices, technologies and legislation for energy reduction.

via the interactive BUILD Up web portal, building professionals and public authorities across Europe can easily share experiences, knowledge and best practices.

6 EBC Newsletter June 2014, Issue 59

Nowadays building energy use and durability issues

are among the most important construction-related

research topics in industrialised countries and the

building sector generally accounts for the largest

share of energy-related carbon dioxide (CO2) emis-

sions. In this respect, retrofit measures are of the

utmost importance for upgrading the existing stock,

thereby reducing energy use and CO2 emissions. But,

many building owners are only interested in the initial

capital cost. Looking at actual risks in performance

and the costs incurred emphasises the need for life

cycle thinking. So, applicable calculation methods are

required in this area.

The ongoing EBC project, ‘Annex 55: Reliability of

Energy Efficient Building Retrofitting-Probability As-

sessment of Performance and Cost’, is addressing this

problem by developing decision support tools and pro-

viding data for energy retrofit measures. The tools are

based on probabilistic methodologies for prediction

of energy use, life cycle cost and functional perfor-

mance.

Case studiesDuring the project, three real retrofitting case stud-

ies have been analysed to show how to apply proba-

bilistic analysis to enhance energy savings, secure

performance and apply life cycle cost analysis. They

are being used to better understand relevant areas

in the planning, construction and operational phases.

Carl-Eric Hagentoft

How do we design and realize robust retrofitting with low energy demand and life cycle costs, while controlling the risk of performance failure? An innovative technique looks set to accomplish them all.

Probabilistic Assessment of Retrofit MeasuresOngoing project: Annex 55

Detached building in Copenhagen, Denmark Source: Rockwool, Denmark

Social housing in porto, portugalSource: vasco freitas

Multi-family residential buildings north of Stockholm in SwedenSource: Johan Stein

7EBC Newsletter June 2014, Issue 59

Developed methodological and analysis techniques

are also being applied to them to enhance discussion,

learning and further refinement. The three case stud-

ies include:

– a detached building in Copenhagen, Denmark,

– social housing in Porto, Portugal, and

– multi-family residential buildings north of

Stockholm in Sweden.

Risk management schemeAn important outcome from the project is a frame-

work for risk assessment that describes how to ana-

lyse a specific retrofitting method that might be ap-

plied to a building. A simplified flowchart to represent

this is shown in the figure below. The framework in-

cludes questions and corresponding actions to give

guidance through the assessment. It sets up a number

of questions that should be answered to find an ac-

ceptable solution for the retrofit measures. Some ex-

ample questions are also listed below.

Retrofit measuresThe project particularly focuses on the Swedish case

study, in which thermal insulation was added on the

cold attic floor in a multi-story building. There are

clear benefits with this retrofitting method, as it is

reasonably fast, convenient and inexpensive, with

quite substantial heat loss reductions. However, prob-

lems with high humidity levels in cold attics have

been increasing significantly over the last decade.

The moist air may condense at the underlay leading

to rot problems. Therefore, it is important to be able

to quantify the risk involved when adding such insu-

lation. For this purpose, several methods have been

investigated. In particular, the Monte Carlo method

has been thoroughly examined.

Using state-of the-art computational programs for

predicting the temperature and moisture levels in the

attic, the risk levels for mould growth and other mois-

ture related damage can be estimated. An important

input for these calculations is the somewhat random

nature of material properties, airtightness, work-

manship and weather. The total economic value of

the retrofit measures can then be evaluated based on

investment cost, the reduced heat loss, as well as the

exemplified moisture related mould growth damage.

Project outcomesThe project has contributed new methods and tools

for integrated evaluation and optimization of retrofit-

ting measures, including energy efficiency, life cycle

cost and durability. The main deliverables, available

later in the year, are 'Guidelines for Practitioners' and

'Probability Based Assessment of Energy Retrofitting

Measures' (tools, assessment schemes and case stud-

ies). It has demonstrated the benefits of the renewal

of the existing building stock and how to achieve reli-

able solutions to decision makers, designers and prac-

titioners.

Further informationwww.iea-ebc.org

Example questions used in the framework are shown below.

the first set of questions relates to the scope of the assessment that can be defined by asking:

– What is to be retrofitted? – What is the aim of the retrofit? – Desired values and consequences? – What are the renovation strategies?

the risk analysis includes questions such as: – What is known about the chosen renovation strategies? – What can cause deviations? – What are the qualifications and quantifications of the

deviations?

Questions on the risk evaluations include: – How well does the renovation strategy meet the purpose of the

renovation? – Are there any limitations with the recommended renovation?

The framework for risk assessment: a simplified flowchart

8 EBC Newsletter June 2014, Issue 59

The existing residential building stock in most indus-

trialised countries is a key area for large scale actions

for energy demand and related carbon dioxide (CO2)

emissions reductions. Indeed, not only is the build-

ings sector a major energy consumer, but at present

there is also a low replacement rate of the existing

stock by new, efficient buildings.

It is possible to reduce energy and CO2 emissions

within the buildings sector by applying energy ef-

ficiency (and conservation) measures and by using

renewable energy sources. The topic of the current

EBC research project, ‘Annex 56: Cost-Effective En-

ergy and CO2 Emissions Optimization in Building

Renovation’, is how to find optimal balances between

these two approaches. The project is looking at how to

combine them to achieve the best results for renova-

tions defined in terms of reductions in energy use, CO2

emissions and consumed resources, along with com-

fort improvement and overall added value achieved.

It is considering how these can be achieved with the

least effort in terms of financial investment, depth

and duration of the intervention, and disturbance to

occupants.

Initial optimisation resultsThe findings of the initial optimisation are now avail-

able from the project for packages of renovation works

Manuela Almeida

Initial results from residential building renovation case studies have shed light on optimal balances between energy efficiency measures and renewable energy supplies to minimise annual costs.

Energy and Carbon Emissions Optimisation in RenovationOngoing project: Annex 56

on residential buildings for annualised life cycle costs,

CO2 emissions and primary energy use. The renova-

tion packages include various measures on the build-

ing envelope in combination with the installation of

alternative heating systems. Some examples are pre-

sented in the figures below. Each point on a curve rep-

resents a specific renovation package, and each curve

represents a different heating system. The point on

the 'oil heating' curve with the highest value for CO2

Comparisons of the cost effectiveness of energy efficient renovation measures for different heating systems based on CO2 emissions and primary energy use for a single-family house in Switzerland.

40

50

60

oil heating

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Emissions per year [kg CO2eq/(a*m2)]

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9EBC Newsletter June 2014, Issue 59

emissions, or with the highest value for primary en-

ergy use, forms the reference case. As more measures

are added to the renovation packages, CO2 emissions

and primary energy use both decrease while costs

only decrease until a certain level is reached - the cost

optimal level - after which they start to rise again. All

the renovation packages with costs below the refer-

ence case are still cost effective, even those above the

cost optimal level.

From the results of evaluations of case study build-

ings located in Austria, Denmark, Norway, Portugal,

Spain, Sweden and Switzerland, the following prelim-

inary conclusions have been drawn:

– The number of building elements renovated is

more important for the energy performance of

the building than the efficiency level of individual

elements.

– The cost optimal levels for energy efficiency

measures with conventional heating systems

tend to be similar to those for renewable energy

systems (RES), such as ground source heat pumps

or biomass wood pellet boilers.

– Synergies are achieved by combining RES with

energy efficiency measures.

– Installing RES reduces CO2 emissions more

significantly than energy efficiency measures.

Shining ExamplesIt is important to promote good examples and good

practice already implemented, as well as to pinpoint

existing and emerging efficient technologies with

potential to be successfully applied. Nine case stud-

ies in six countries were identified to be successfully

completed national demonstration projects. This bro-

chure termed ‘Shining Examples’ is now available for

download.

An example of these is a residential building from Ka-

pefenberg in Austria, shown below. The findings from

an analysis of these case studies are:

– The main barriers associated with the renovation

process were of an administrative nature, for

example delays caused by poor project leadership,

or were related to financial issues.

– All of the Shining Examples confirm that the

opportunity for optimised renovation is created by

the need for maintenance or routine renovation.

Renovation should allow for the actions, products

and services necessary to guarantee the normal

use, safety, legal function and aesthetics of the

existing building and, if necessary, for upgrading

it to current functional needs.

– Not only did all renovation projects achieve better

energy performance, but also improved the indoor

climate, comfort and aesthetics. These benefits,

if clearly communicated to building owners,

managers and occupants can help to overcome some

of the barriers they are currently experiencing.

– The average primary energy savings calculated for

all of the analysed case studies was more than 70%.

Further informationwww.iea-ebc.org

the residential building in Kapfenberg, Austria, before (left) and after the renovation process (right).

10 EBC Newsletter June 2014, Issue 59

Several recent studies have shown that real thermal

building envelope performance after construction may

deviate significantly from the theoretical design. Con-

sequently, there is growing interest in full scale on-

site testing to evaluate as-built thermal performance.

However, experience has shown that the outcome of

many on-site testing activities can be questioned in

terms of accuracy and reliability. Additionally, their

applicability to different climatic regions is not well

established. The focus of nearly all full scale testing

is on the assessment of components and buildings,

but often overlooking the need for reliable assessment

methods and quality assurance.

So to address these issues, the goal of the EBC research

project, 'Annex 58: Reliable Building Energy Perfor-

mance Characterisation Based on Full Scale Dynamic

Measurements', is to develop the necessary knowl-

edge, tools and research networks to achieve reliable

on-site dynamic testing and data analysis methods.

These can then be used to characterise the actual en-

ergy performance of components and of whole build-

ings. In a first simple trial, a series of 'round robin'

physical experiments are being performed on a test

box by separate teams. In round robin experiments,

the partner organisations in different countries each

take turns to perform full scale testing under real

world climatic conditions.

Round robin experiments A round robin experimental approach has been de-

vised to examine the effectiveness of different on-site

testing and data analysis methods. The test box used

has exterior dimensions of 120 cm x 120 cm x 120 cm.

The floor, roof and wall components of the box are all

identical and of 12 cm thickness, apart from a win-

dow in one side. A non-conducting frame ensures that

the test box is not subject to thermal influences from

the ground. This box, assembled by one of the partici-

pants, can be regarded as a scale model of a building,

with fabric properties unknown to all other partici-

pants. The measured data obtained are distributed to

all participants, who then have to try to determine the

thermal performance of the test box’s fabric.

At the various test sites, a range of different experi-

ments are performed, including periods with free

floating temperatures, heating to constant inside tem-

perature, and dynamically imposed heating sequenc-

es. During these experiments, heat fluxes (i.e. heat

flow rates per unit area) on all internal surfaces, in-

ternal and external surface temperatures, indoor air

temperature and delivered heating energy within the

box are recorded. Additionally, an outdoor weather

station comprehensively measures relevant climatic

boundary conditions. During winter 2012, the test

box was deployed in Limelette, Belgium. It was sub-

sequently transferred to Spain, where it was tested

under the summer conditions of Almeria, Spain. It

has recently been situated in Bilbao, Spain for winter

testing.

Characterising thermal performance Based on the data measured during the physical ex-

periments, a range of different analysis methods are

being applied by the teams to attempt to characterise

the thermal performance of the test box. The methods

Staf Roels

The accuracy and reliability of building envelope performance measurements have lately come under scrutiny. Can taking turns in testing make for more truthful thermal assessments?

Real Thermal Performance of BuildingsOngoing project: Annex 58

11EBC Newsletter June 2014, Issue 59

test box at the measuring sites: (left) during winter at Limelette, Belgium (right) during summer at Almeria, Spain.

vary from a simple averaging approach to advanced

dynamic techniques as follows:

– An averaging method: This is the simplest technique

used to estimate the steady state (i.e. assumed

constant) thermal resistance of building elements

from in situ surface temperature and heat flux

measurements. It assumes that the average heat

flow rate and temperatures over a sufficiently long

period of time will give a reliable estimate of the

true values. Consequently, this method is expected

to be useful, for example, for interpreting the data

collected during the winter conditions in Belgium,

but not for the summer data from Spain.

– Co-heating: A data analysis method to determine

steady state properties of a building based on

linear regression is known as the co-heating test,

which requires results from heating to constant

inside temperature. By fitting an assumed linear

relationship between the heat input and indoor

to outdoor temperature difference, the overall

heat loss coefficient can be determined. Applying

multiple linear regression extends this concept

to provide valuable information on the solar

transmittance.

– State space modelling: State space ('grey box')

models are based on a combination of prior physical

knowledge and statistical relationships and identify

the previously unknown thermal parameters of the

system using dynamic data analysis. Generally a

'forward selection' approach is used: First of all a

very simple model is fitted, which is then extended

step by step until no improvement is found

compared to the previous model and all relevant

physical phenomena have been incorporated.

Next project stepsThe objective of the round robin experiments is to

perform well-controlled comparative testing and

data analysis for determining building thermal per-

formance. This work is exploring how different tech-

niques can be applied to characterise the performance

of the test box ranging from (quasi-) steady state tech-

niques to dynamic characterisation. After this has

been concluded, the next step for this research project

is to investigate how these methods can be best ap-

plied to determine the thermal performance of real

buildings. Particular attention is being paid to the

possibilities for and limitations of grey box models in-

formed by measured dynamic thermal behaviour of

buildings in use, for both summer and winter condi-

tions.

Further informationwww.iea-ebc.org

12 EBC Newsletter June 2014, Issue 59

The purpose of building heating, ventilation and air

conditioning (HVAC) systems is to maintain the qual-

ity of the indoor climate, including meeting required

levels of air temperature, humidity and indoor air

quality. But, conventional systems have not always

been developed with energy efficiency as a priority.

In fact, they can include inefficient processes that use

more energy than is necessary to produce the de-

sired environmental conditions. However, since the

temperatures of heating and cooling sources directly

influence HVAC system energy use, high temperature

cooling and low temperature heating (HTC and LTH)

systems have the potential to improve energy efficien-

cy.

One of the aims of the ongoing EBC project ‘Annex

59: High Temperature Cooling and Low Temperature

Heating in Buildings’ is to develop novel systems with

fully utilized sources of heat and cold, high efficien-

cy transportation and appropriate indoor terminals.

Specifically, it is considering how to avoid unneces-

sary offset of cooling and heating, dehumidification

and humidification, mixing losses of cold and hot flu-

ids, or unnecessary or inappropriate transfer losses

due to heat exchange. The project is evaluating HVAC

systems in buildings from a new angle and is intend-

ed to provide a new perspective to their design. This

will be principally for the benefit of building own-

ers, designers and equipment manufacturers. The

scope includes suitable systems for major commercial

buildings, such as offices, buildings containing large

enclosures, and so on.

Minimising temperature differencesThis project introduces a new concept for analysis and

design of HVAC systems. This involves redesigning

conventional systems by reducing mixture and trans-

fer losses to produce HTC and LTH systems. It is im-

portant to minimise temperature differences in HVAC

systems, because high differences result in reduced

efficiencies and therefore in increased energy use. It

is focusing on temperature differences throughout the

systems and within the indoor spaces that they serve,

and on how these can be minimized in highly energy

efficient buildings. Temperature differences within

HVAC systems can be classified into three types, aris-

ing from:

– heat and moisture exchange,

– heat transmission through fluid media, and

– thermal mixing losses in indoor spaces due to

indoor terminal devices.

In particular, reduced temperature differences can be

achieved by:

– proper design of heat exchange processes, including

moisture,

– minimization of mixture losses through appropriate

arrangement of indoor terminals, and

– efficient heat transmission from source to fluid

media and then to occupied spaces.

Initial resultsA number of findings have emerged from the work al-

ready completed, including:

– Separate temperature and humdity controls is the

basic requirement for HTC and LTH systems, since

the requirements for heating or cooling sources

differ for air temperature and humidity levels.

Yi Jiang

An innovative concept for HVAC system analysis and design is producing more efficient cooling and heating systems by reducing mixing and transfer losses.

Rethinking HVAC systemsOngoing Project: Annex 59

13EBC Newsletter June 2014, Issue 59

– Outdoor air handling equipments, especially for

treatment of humidity level, is the main components

in HTC and LTH systems.

– Low quality sources can be used efficiently by

applying liquid or solid desiccant dehumidification.

– Based on proper humidity treatment, indoor

temperature can be controlled by indoor terminals

with high temperature cooling sources and low

temperature heating sources.

0 1 0 1.2indoor 25 25 Tc 45 45air 25 16 9 Cooling w 40 35water 12 7 5 Ta,s 30 30Te 4.5 4.5

fresh air 35 17.514.6 14.6

0

10

20

30

40

50

-0.25 0 0.25 0.5 0.75 1 1.25 1.5

Tem

pera

ture

T(o

C)

Transferred heat Q (kW)

ΔT6

ΔT4

Indoor temperature

Outdoor temperature

Air in FCU

Chilled water

Condensing Temperature

Cooling water

∆T1

∆T2

∆T5

∆T 'Chiller task

∆T7

Q0.5Q

∆T3

Evaporating Temperature

∆T Real task

– Radiant terminals, for example underfloor heating

and cooling and radiant panels are well suited

for HTC and LTH systems. Static and dynamic

performance of radiant terminals is planned to be

further examined, especially in combination with

direct solar radiation.

Further information www.iea-ebc.org

the schematic diagram (above left) shows an illustrative relationship between temperature and transferred heat in a conventional HvAC system, with the sources of the temperature differences also explained (above right).

When the difference between the indoor temperature and outdoor wet bulb temperature (Dt) is only 2 K, the condenser to evaporator temperature difference in the chiller (Dt') is 32 K under typical summer conditions. the temperature changes mainly during the heat transportation process from the cooling or heating sources to the indoor space, and from the condenser to the outdoor environment.

In this conventional HvAC system, air is dehumidified by cooling it to condense moisture, which requires the cooling source’s temperature be lower than the indoor dew point temperature and much lower than that required to simply cool the indoor space. the coupled treatment of cooling and dehumidification results in an increase in temperature difference in the system. In addition, losses due to temperature differences arise inside the conditioned indoor space, due to variations between the constant supply air conditions and varying levels of internal heat and moisture gains.

Temperature differences arising from heat exchange and transfer in a conventional HVAC system

Energy consumptionDt : CompressorDt1: fCU fanDt3: Chilled water pumpDt6: Cooling water pump

Heat and mass transfer areaDt2: fCUDt4: EvaporatorDt5: CondenserDt7: Cooling tower

14 EBC Newsletter June 2014, Issue 59

Annex 51: Energy Efficient Communities (completed)

This recently completed project has successfully delivered practical guidance for urban planners, decision mak-

ers and stakeholders on how to achieve ambitious energy and CO2 reduction targets at local and urban scales. It

has addressed small units, such as neighbourhoods or quarters, as well as whole towns or cities. The project has

generated the necessary knowledge and means to be able to define reasonable goals in terms of energy efficiency,

energy conservation and CO2 abatement at the community level. The project deliverables are the ‘Guidebook to

Successful Urban Energy Planning’ is aimed at decision makers in urban administrations, developers and urban

planners and the ‘District Energy Concept Adviser’ - an electronic tool to support municipal administrations and

urban planners faced with the task of developing and comparing options for integrated energy systems for neigh-

bourhoods, either for new developments or for retrofit projects (see www.iea-ebc.org for how to get deliverables).

EBC International ProjectsNew and Completed Projects

Annex 53: Total Energy Use in Buildings: Analysis and Evaluation Methods (completed)

Improving the understanding of how various factors influence the total energy use in buildings, and developing

analysis and evaluation methods to support this were the main goals of this recently completed project. Fifteen

countries were involved in this project and more than 100 researchers participated. The final report on ‘Total

Energy Use in Buildings, Analysis and Evaluation Methods’ has been published on www.iea-ebc.org

together with six supporting documents that explain the underlying work in detail. The supporting documents

cover the following topics:

– definition of terms,

– occupant behaviours and modelling,

– case study buildings,

– data collection systems for the management of building energy system,

– statistical analysis and prediction method, and

– energy performance analysis.

Annex 66: Definition and Simulation of Occupant Behavior in Buildings (new)

Despite the enormous impact of occupant behavior on building performance, this factor is often not given the

same recognition as building envelopes, lighting, and heating, cooling, and ventilation during design, construc-

tion, and operation of buildings. This subject will be investigated by this newly approved project with the objec-

tives to:

– create quantitative descriptions and classifications for energy-related occupant behaviour in buildings,

– develop effective calculation methodologies for occupant behaviour,

– implement occupant behaviour models within building energy modelling tools, and

– demonstrate occupant behaviour models in building design, evaluation and operation optimization using case

studies.

Contact: Hiroshi Yoshinoyoshino@sabine.pln.archi.tohoku.ac.jp

Contact: Da Yanyanda@tsinghua.edu.cn

Tianzhen Hong thong@lbl.gov

Contact: Reinhard Jank reinhard.jank1@ewe.net

15EBC Newsletter June 2014, Issue 59

Annex 5 Air Infiltration and Ventilation Centrethe AIvC carries out integrated, high impact dissemination activities with an in depth review process, such as delivering webinars, workshops and technical papers.Contact: Dr peter Woutersaivc@bbri.be

Annex 52 Towards Net Zero Energy Solar Buildings (NZEBs)The project is achieving a common understanding of net-zero, near net-zero and very low energy buildings concepts and is delivering a harmonized international definitions framework, tools, innovative solutions and industry guidelines.Contact: Josef AyoubJosef.Ayoub@RNCan-NRCan.gc.ca

Annex 54 Integration of Micro-generation and Related Energy Technologies in BuildingsA sound foundation for modelling small scale co-generation systems underpinned by extensive experimental validation has been established to explore how such systems may be optimally applied.Contact: Dr Evgueniy Entcheveentchev@nrcan.gc.ca

Annex 55 Reliability of Energy Efficient Building Retrofitting - Probability Assessment of Performance and Cost The project is providing decision support data and tools concerning energy retrofitting measures for software developers, engineers, consultants and construction product developers. Contact: Dr Carl-Eric Hagentoftcarl-eric.hagentoft@chalmers.se

Annex 56 Cost-Effective Energy and CO2 Emission Optimization in Building RenovationThe project is delivering accurate, understandable information and tools targeted to non-expert decision makers and real estate professionals. Contact: Dr Manuela Almeida malmeida@civil.uminho.pt

Annex 57 Evaluation of Embodied Energy and CO2 Emissions for Building ConstructionThe project is developing guidelines to improve understanding of evaluation methods, with the goal of finding better design and construction solutions with reduced embodied energy and related CO2 emissions.Contact: Prof Tatsuo Okaokatatsuo@e-mail.jp

Annex 58 Reliable Building Energy Performance Characterisation Based on Full Scale Dynamic MeasurementsThe project is developing the necessary knowledge, tools and networks to achieve reliable in-situ dynamic testing and data analysis methods that can be used to characterise the actual energy performance of building components and whole buildings. Contact: Prof Staf Roelsstaf.roels@bwk.kuleuven.be

Annex 59 High Temperature Cooling and Low Temperature Heating in BuildingsThe project aim is to improve current HVAC systems, by examining how to achieve high temperature cooling and low temperature heating by reducing temperature differences in heat transfer and energy transport processes.Contact: Prof Yi Jiang jiangyi@tsinghua.edu.cn

Annex 60 New Generation Computational Tools for Building and Community Energy SystemsThe project is developing and demonstrating new generation computational tools for building and community energy systems based on the non-proprietary Modelica modelling language and Functional Mockup Interface standards.Contact: Michael Wetter, Christoph van Treeckmwetter@lbl.gov, treeck@e3d.rwth-aachen.de

Annex 61 Business and Technical Concepts for Deep Energy Retrofit of Public BuildingsThe project aims to develop and demonstrate innovative bundles of measures for deep retrofit of typical public buildings to and achieve energy savings of at least 50%. Contact: Dr Alexander M. Zhivov, Rüdiger Lohse Alexander.M.Zhivov@erdc.usace.army.mil, ruediger.lohse@kea-bw.de

Annex 62 Ventilative Cooling This project is addressing the challenges and making recommendations through development of design methods and tools related to cooling demand and risk of overheating in buildings and through the development of new energy efficient ventilative cooling solutions.Contact: Per Heiselbergph@civil.aau.dk

Annex 63 Implementation of Energy Strategies in CommunitiesThis project is focusing on development of methods for implementation of optimized energy strategies at the scale of communities.Contact: Helmut Strasserhelmut.strasser@salzburg.gv.at

Annex 64 LowEx Communities - Optimised Performance of Energy Supply Systems with Exergy Principles This project is covering the improvement of energy conversion chains on a community scale, using an exergy basis as the primary indicator.Contact: Dietrich Schmidtdietrich.schmidt@ibp.fraunhofer.de

Annex 65 Long-Term Performance of Super-Insulating Materials in Building Components and SystemsThis project is investigating potential long term benefits and risks of newly developed super insulation materials and systems and to provide guidelines for their optimal design and use. Contact: Daniel Quenarddaniel.quenard@cstb.fr

EBC International ProjectsCurrent Projects

16 EBC Newsletter June 2014, Issue 59

CHAIRAndreas Eckmanns (Switzerland)

VICE CHAIRDr Takao Sawachi (Japan)

AUSTRALIAStefan Preuss Stefan.Preuss@sustainability.vic.gov.au

AUSTRIAIsabella Zwerger Isabella.Zwerger@bmvit.gv.at

BELGIUMDr Peter Wouterspeter.wouters@bbri.be

CANADA Dr Morad R AtifMorad.Atif@nrc-cnrc.gc.ca

P.R. CHINAProf Yi Jiang jiangyi@tsinghua.edu.cn

CZECH REPUBLICTo be confirmed DENMARKRikke Marie Haldrmh@ens.dk

FINLANDDr Markku J. Virtanenmarkku.virtanen@vtt.fi

FRANCEPierre Hérantpierre.herant@ademe.fr

GERMANYMarkus Kratz m.kratz@fz-juelich.de

GREECETo be confirmed

IRELANDProf J. Owen Lewisj.owen.lewis@gmail.com

ITALYMichele Zinzimichele.zinzi@enea.it

JAPANDr Takao Sawachi (Vice Chair)sawachi-t92ta@nilim.go.jp

REPUBLIC OF KOREADr Seung-eon Lee selee2@kict.re.kr

NETHERLANDSPiet Heijnenpiet.heijnen@rvo.nl

NEW ZEALANDMichael Donnmichael.donn@vuw.ac.nz

NORWAYEline Skardeska@rcn.no

POLANDDr Beata Majerska-Palubickabeata.majerska-palubicka@polsl.pl

PORTUGALProf Eduardo Maldonadoebm@fe.up.pt

SPAIN José María Campos josem.campos@tecnalia.com

SWEDEN Conny Rolénconny.rolen@formas.se

SWITZERLANDAndreas Eckmanns (Chair)andreas.eckmanns@bfe.admin.ch

UKProf Paul Ruysseveltp.ruyssevelt@ucl.ac.uk

USARichard Karneyrichard.karney@ee.doe.gov

EBC Executive Committee Members

IEA SecretariatMark LafranceMarc.LAfRANCE@iea.org

EBC SecretariatMalcolm Ormeessu@iea-ebc.org

www.iea-ebc.org